Partial denture with movable retaining arm



Aug. 23, 1966 v. J. ODDO, JR 3,267,574

PARTIAL DENTURE WITH MOVABLE RETAINING ARM Filed March 6, 1963 Patented August 23, 1966 ice 3,267,574 PARTIAL DENTURE WITH MOVABLE RETATNENG ARM Vincent J. Oddo, J12, 161 Bretton Woods Drive, Cranston, RI. Filed Mar. 6, 1963, Ser. No. 263,196 8 Claims. (Cl. 325) My present invention relates to the retention of partial dentures and more particularly with the retention of a partial denture by the use of a pin or arm that is placed into position after the partial denture is inserted in the mouth.

The principal object of the present invention is to provide a construction in which a pin or arm or movable portion of a clasp must be retracted to allow insertion past the widest portion of a tooth and later inserted or placed into position by mechanical movement by the fingers, where it will engage an undercut and afford retention.

Another object of the present invention is to provide a means and method of retaining a partial denture which eliminates the use of metal clasps made of wire or cast stainless steel which are unsightly and create continual tension on the teeth and surrounding structure when the partial is seated in the mouth.

Another object of the present invention is to provide a partial denture which is retained in position without the use of spring tensions for engaging an undercut n the outside and inside of a tooth. Since the position of these clasped arms are determined by the contour of the tooth, and most teeth have their widest portion near the center of the tooth, and the narrowest portion at the gingiva, most clasps used today are in the center portion of the tooth and are readily seen when the patient smiles.

Another object of the present invention is to provide a partial denture retaining means which requires no preparation of the teeth for the retention.

Another object of the present invention is to provide a partial denture retaining means which eliminates the use of all outside arms.

With the above and other objects and advantageous features in view my invention consists of a novel arrangement of parts more fully disclosed in the detailed description following in conjunction with the accompanying drawings and more particularly defined in the appended claims.

In the drawings,

FIG. 1 is an enlarged perspective view of a partial denture retaining means embodying my invention.

FIG. 2 is an enlarged transverse section thereof taken through the base.

FIG. 3 is an enlarged plan view of the movable arm unit in closed position.

FIG. 4 is a view similar to FIG. 3 with the movable arm unit in open position.

FIG. 5 is a perspective view of the movable arm unit.

FIG. 6 is a fragmentary perspective view of one side edge of the locking unit.

The conventional devices in use today for retaining a partial denture uses a constant spring tension which must be exerted by a clasp to keep the denture in the mouth. This spring tension is obtained by placing the ends of the clasp below the height of the contour of the tooth, and in the case of orthodontic movement of the tooth in due time, pain, gum recession and eventual loss of the tooth will result. The wire or cast stainless steel clasp can flex only Within certain limits. It must be placed slightly belowthe height of the contour of the tooth and it must spring over the height of the contour to remove the partial denture and spring back to its original position. These limits cannot be exceeded, so that if the arm should spring out of position it will no longer afford the necessary retention. The present invention provides an entirely new principle for retaining a partial denture in the mouth. The unit of the present invention uses a movable arm or pin which allows the partial denture to be placed into the mouth and is then moved into position to grasp the undercut area of the tooth at the gingiva. The device consists of a locking mechanism having two associated portions. One portion is embedded in the plastic of the partial denture and comprises a metal housing and pivot member for retaining the other portion which is a movable pin or arm which can be moved forward to engage the undercut of the tooth in the space between the teeth or backward toward the inside of the mouth to allow removal of the partial denture when the pin or arm is disengaged.

Referring more in detail to the drawings, the artificial teeth comprising the partial denture are normally mounted on a frame 19 illustrated in FIG. 1 with only a single tooth 11 in position. One end of the frame is illustrated as having conventional means 12 for engaging a natural tooth 13 at one end of the partial denture. The other end of the partial denture is provided with a plastic base 14 on which the tooth 11 is mounted. Extending from the forward edge of the tooth 11 and plastic portion 14 is a short arcuate metal supporting member 15 which engages the side of the natural tooth 16 at the other end of the gap to be filled. The arcuate portion 15 merely braces the partial denture in position but does not lock it against movement. Locking action is provided by the construction shown in FIGS. 2 to 6 inclusive.

The locking unit comprises a fiat housing 17 in the form of a U-shaped member having a top, a bottom and a rear wall connecting the top and bottom. The housing 17 is embedded in the plastic 14 as shown in FIG. 2. The rear edge 18 is embedded in the plastic and the front edge is open to the rear portion of the partial denture as illustrated in FIG. 1. The housing 17 is provided at one side edge with upstanding lugs or teeth 19 for embedment in the plastic material 14 to lock it in position. Adjacent the other open side edge is a pivot pin 28' extending vertically through the housing as shown in FIGS. 2 and 5, the pin extending considerably above and below the housing to also form embedded portions in the plastic 14 as shown in FIG. 2. The pivot pin 20 and the lugs 19 therefore serve to immovably retain the housing 17 in the plastic material 14. Pivotally mounted in the housing 17 is the arm retaining base 21. The base 21 is of such width that a portion thereof 22 extends from the rear of the housing as illustrated in FIGS. 1, 3 and 5 and having an enlarged finger engaging portion 23 opposite a cut out portion of the base 24 to permit the member 21 to be pivoted around the pin 20 by manually pressing the portion 23 into the portion 24 of the base as shown in FIG. 4. The member 21 can therefore be moved around the pivot pin 20 from the position shown in FIG. 3 to the position shown in FIG. 4 and back by pressure against the portion 23. The rear end of the base arm member 21 is provided with an indentation 25. The bottom of the housing 17 is bent upwardly to partially close the side edge below the lugs 19 as shown in FIGS. 4 and 6. A leaf spring 26 is inserted into the housing between the turned up portion of the bottom and the rear end of the base 21 as shown in FIGS. 3, 4 and 6. The lower end of the leaf spring 26 is provided with a bent portion 27 adapted to enter the small indentation 25 on the base 21 as shown in FIG. 3 to releasably retain the member 21 in the position shown in FIG. 3.

In the view of the various casting operations an integral spring tends to lose its resiliency. Therefore the spring 26 is preferably inserted just before the housing is embedded into the plastic into the position shown in FIG.

2. The upper end of the spring may be bent over to lock into the plastic. if it is desired to change the spring a hole must be drilled in the plastic parallel to the side edge to free the bent over end from the plastic.

When the arm base 21 is pivoted as shown in FIG. 4 by pressure on the portion 23 it will snap past the finger 27 of the spring 26. In the return movement, when the arm is swung back into the position shown in FIG. 3, the finger 27 will snap into the cut out portion 25 to releasably lock the arm into the position shown in FIGS. 3 and 5.

The forward end of the arm retaining base 21 is provided with a plurality of cut out portions 23 and 29. The arm 30 illustrated in full lines in FIG. 1 and in dotted lines in FIG. 5 comprises the movable locking arm for locking the denture in position. This arm is shaped by the dentist or the technician and cast on to the end of the base portion 21 interlocking with the portions 23 and 29 which may also be provided with openings as shown in FIGS. 3, 4 and 5. The arm 3 is shaped to snugly pass around the adjacent tooth 16 when the end enters the space between the tooth to and the next tooth 31. If found necessary the arm can be extended across to the next tooth 32 and the space between the teeth 31 and 33. as shown in FIG. 1, or both spaces can also be used by pressing a compound arm which will extend into one, two or more spaces. The end of the arm 39 can be made sufiicicntly long to pass forwardly through the space between the teeth until it is barely visible from the front to positively lock the partial denture in position. Removal merely means depressing the portion 23 of the base until it pivots into the position shown in FIG. 4 removing the end of the arm 3% from between the teeth and allowing the partial denture to be taken out.

The illustrated construction has many advantages over the normal spring clasped arms. Please note that no preparation of the teeth for the retention of the partial denture is necessary. The partial denture of the present invention and its arm 39 is built and shaped to accommodate the tooth already in the mouth and no preparation of these teeth is necessary. The Buccal arms are eliminated so that there is no ugly metal shown on the outside of the teeth. No spring tension is provided in on or otf position and there is no stress on the teeth dur ing insertion or removal. This extends the life of the. natural teeth on either side of the opening which the partial denture is bridging. Furthermore, the partial denture has no spring clasp which must be loosened or which may need adjustment. It is therefore inexpensive and requires no further visits to the dentist for adjustments. It can be used with chrome or gold and is small, compact and smooth in appearance.

While the illustrated form shows the use of a conventional tension arm device 12 for anchoring the rear portion on the tooth 13, the device can be placed at both ends of the teeth or else the rear port-ion can be braced against the tooth 13 by merely using a small arcuate portion such as the arm 15 at the other end.

The device is simple in construction and easy and economical to manufacture and assemble. Other advantages of the present invention will be readily apparent to a person skilled in the art.

I claim:

1. A denture including a frame, a plastic bed on said frame, an artificial tooth mounted in said bed, means for bracing one end of said denture against the side edge of an adjacent natural tooth, and means for releasably locking said braced end to the rear of the adjacent natural teeth, said locking means comprising an arm pivotally mounted behind said denture, said arm being adapted to pivotally enter the space between the adjacent natural teeth at the gum line, means for yieldingly retaining said arm in locking position, a housing embedded in said plastic bed, a member pivotally mounted in said housing and extending from said bed, said arm being mounted on said pivoted member.

2. A denture including a frame, a plastic bed on said frame, an artificial tooth mounted in said bed, means for bracing one end of said denture against the side edge of an adjacent natural tooth, and means for releasably locking said braced end to the rear of the adjacent natural teeth, said locking means comprising an arm pivotally mounted behind said denture, said arm being adapted to pivotally enter the space between the adjacent natural teeth at the gum line, and means for releasably locking and yieldably retaining said arm in position between the natural teeth, a housing embedded in said plastic bed, a member pivotally mounted in said housing and extending from said bed, said arm being mounted on said pivoted member.

3. A denture including a frame, a plastic bed on said frame, an artificial tooth mounted in said bed, means for bracing one end of said denture against an adjacent natural tooth, and means for releasably locking said braced end to the adjacent natural teeth, said locking means comprising an arm pivotally mounted behind said denture, said arm being adapted to pivotally enter the space between the adjacent natural teeth at the gum line, a housing embedded in said plastic bed, a member ivotally mounted in said housing and extending from said bed, said arm being mounted on said pivoted memher, and a spring in said housing for yieldingly retaining said arm in locking position.

d. A denture including a frame, a plastic bed on said frame, an artificial tooth mounted in said bed, means for bracing one end of said denture against an adjacent natural tooth, and means for releasably locking said braced end to the adjacent natural teeth, said locking means comprising an arm pivotally mounted behind said denture, said arm being adapted to pivotally enter the space be tween the adjacent natural teeth at the gum line, and means for releasably locking said arm in position between the natural teeth, a housing embedded in said plastic bed, a member pivotally mounted in said housing and extending from said bed, said arm being mounted on said pivoted member, and a spring in said housing for yieldingly retaining said arm in locking position.

5. A denture including a frame, a plastic bed on said frame, an artificial tooth mounted in said bed, means for bracing one end of said denture against an adjacent natural tooth, and means for releasably locking said braced end to the adjacent natural teeth, said locking means comprising an arm pivotaliy mounted rbehind said denture, said arm being adapted to pivotally enter the space be tween the adjacent natural teeth at the gum line, means for yieldingly retaining said arm in locking position, a housing embedded in said plastic bed, a member pivotally mounted in said housing and extending from said bed, said arm being mounted on said pivoted member, said pivoted member having a manually engageable rear portion extending from said housing to manually pivot said arm about its pivot into open position.

6. A denture including a frame, a plastic bed on said frame, an artificial tooth mounted in said bed, means for bracing one end of said denture against an adjacent natural tooth, and means for releasably locking said braced end to the adjacent natural teeth, said locking means comprising an arm pivotally mounted behind said denture, said arm being adapted to pivotally enter the space between the adjacent natural teeth at the gum line, and means for releasably lociring and yieldably retaining said arm in position between the natural teeth, a housing embedded in said plastic bed, a member pivotally mounted in said housing and extending from said bed, said arm being mounted on said pivoted member, said pivoted member having a manually engageable rear portion extending from said housing to manually pivot said arm about its pivot into open position.

7. A denture including a frame, a plastic bed on said frame, an artificial tooth mounted in said bed, means for bracing one end of said denture against an adjacent natural tooth, and means for releasably locking said braced end to the adjacent natural teeth, said locking means comprising an arm pivotally mounted behind said denture, said arm 'being adapted to pivotaily enter the space between the adpacent natural teeth at the gum line, a housing embedded in said plastic bed, a member pivotally mounted in said housing and extending from said bed, said arm being mounted on said pivoted member, said pivoted member having a manually engageable portion extending from said housing to manually pivot said arm into open positiOn, and a spring in said housing for yieldingly retaining said arm in locking position.

3. A denture including a frame, a plastic bed on said frame, an artificial tooth mounted in said bed, means for bracing one end of said denture against an adjacent natural tooth, and means for releasably locking said braced end to the adjacent natural teeth, said locking means comprising an arm pivotally mounted behind said denture, said arm being adapted to pivotally enter the space be- References Cited by the Examiner UNITED STATES PATENTS 1,251,912 1/1918 Nordstrom 325 1,401,243 12/1921 Eager 32-5 2,886,890 5/1959 Schnell 322 RICHARD A. GAUDET, Primary Examiner.

ROBERT E MORGAN, Examin r. 

1. A DENTURE INCLUDING A FRAME, A PLASTIC BED ON SAID FRAME, AN ARTIFICAL TOOTH MOUNTED IN SAID BED, MEANS FOR BRACING ONE END OF SAID DENTURE AGAINST THE SIDE EDGE OF AN ADJACENT NATURAL TOOTH, AND MEANS FOR RELEASABLY LOCKING SAID BRACED END TO THE REAR OF THE ADJACENT NATURAL TEETH, SAID LOCKING MEANS COMPRISING AN ARM PIVOTALLY MOUNTED BEHIND SAID DENTURE, SAID ARM BEING ADAPTED TO PIVOTALLY ENTER THE SPACE BETWEEN THE ADJACENT NATURAL TEETH AT THE GUM LINE, MEANS FOR YIELDINGLY RETAINING SAID ARM IN LOCKING POSITION, A HOUSING EMBEDDED IN SAID PLASTIC BED, A MEMBER PIVOTALLY MOUNTED IN SAID HOUSING AND EXTENDING FROM SAID BED, SAID ARM BEING MOUNTED ON SAID PIVOTED MEMBER. 